Test for new introduced JSONArray(int) constructor.

Link: stleary/JSON-java#516

1. Checked with input parameter: 0
2. Checked with input parameter: positive number
3. Checked with input parameter: negative number

If input parameter is negative number JSONException is thrown:
    JSONArray initial capacity cannot be negative.

src/test/java/org/json/junit/JSONArrayTest.java

@@ -2,6 +2,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
@@ -1070,4 +1071,21 @@ public void toList() {
         assertTrue("Removing an entry should succeed", list.remove(2) != null);
         assertTrue("List should have 2 elements", list.size() == 2);
     }
+
+    /**
+     * Attempt to create a JSONArray with an unclosed array.
+     * Expects an exception
+     */
+    @Test
+    public void testJSONArrayInt() {
+    	assertNotNull(new JSONArray(0));
+    	assertNotNull(new JSONArray(10));
+        try {
+        	assertNotNull("Should throw an exception", new JSONArray(-1));
+        } catch (JSONException e) {
+            assertEquals("Expected an exception message", 
+                    "JSONArray initial capacity cannot be negative.",
+                    e.getMessage());
+        }
+    }
 }